1. Field of the Invention
The present invention relates to a manifest mechanism in a broadcast involved system. More particularly, the present invention relates to a method for receiving manifest information by a client from a broadcast involved system.
2. Description of the Related Art
A manifest is proposed in an adaptive stream solution. It provides information about an adaptive stream, e.g., which bitrate is used for each segment. Accordingly, a terminal could choose the proper segment based on its condition.
FIG. 1A illustrates a manifest of parameters according to the related art:
Referring to FIG. 1A, the parameters of a manifest include the following attributes:
I. Universal Resource Locator (URL) Template: A unique URL created by combining a fixed part, a segment Identifier (ID), and a track ID. It consists of URLs of each segment along with a track ID and a segment ID. The URL Template is used for accessing each segment of an adaptive stream. It can be overridden by a URL in each segment if necessary. For example:
//example.com/vod/movie/18888/Track/{TrackID}/Segments/{segmentID}.
II. NextAdaptiveControlURL: Used to indicate the next eXtensible Markup Language (XML) URL, which is used for continuous presentation. It is optional and can be used in a case of live adaptive streaming or for an advertisement user.
III. RefDataURL: Used to indicate a part of or a complete head data (.ref). It is optional when segments can decode themselves.
IV. Track: A set of contiguous segments of a particular type with different bitrates.                i. ID: Indicates a Track ID.        ii. Types: Indicates a type of Track and can be a Video, an Audio, Packed data (combined Video and Audio), and an I-Frame.        iii. BitRate: Indicates a Bit rate of segments in a Track.        iv. StartTime: An optional feature to indicate a Time stamp which specifies the start-time of a track.        v. SegmentStartID: An optional feature to indicate an initial ID of segments which belong to the track.        vi. SegmentDuration: An optional feature to indicate a duration of each segment.        vii. SegmentCount: An optional feature to indicate a total number of segments which belong to the track.        viii. Segment: A Segment is a concatenation of some basic units, each consisting of a fragment made of only audio or video data, or both audio and video data, divided based on a specific time interval. It is a basic unit transfer between a server and a client. It is also assigned a time stamp for locating or A/V sync. More specifically, an element segment is optional. If the optional attributes of a track element are specified, all of the information of each segment can be deduced so that the element segment is unnecessary.                    ID: Indicates a Segment ID.            StartTime: A Starting time of the segment.            Duration: A Duration of the segment.            URL: Optional when a URL Template is used. It can be specified for special usage (e.g., Contents or an Ad Video from other server) and the URL Template would be ignored for this segment.                        
However, a problem may occur when the current manifest is used for an interactive network. That is, the manifest could be updated and there is no mechanism to support the manifest in the broadcast involved network. In the point to point network, the client could query the server for the next updated manifest. If it is ready, the server will send it to the client, otherwise, the server will send a response without an updated manifest.
Therefore, there is a need for a method and an apparatus for receiving manifest information by a client from a broadcast involved system.